I recently encountered an issue with my Z-Wave thermostats that I wanted to share and hopefully help others who might be facing similar challenges. I have 8 Secure/IQE SRT321 (aka Horstmann HRT4-ZW) Z-Wave wall thermostats, which have been working perfectly on my C4 hub. However, after migrating to C7, one of them stopped responding to mode changes. This was puzzling because the other 7 thermostats worked without any issues.
After some research and reaching out to the community, I discovered that the problem might not be with the hub but with the device itself. I consulted with @meavydev, who mentioned that he had encountered the same issue and verified with a zniffer that the mode changes were indeed being sent to the hub. This suggested that the problem was isolated to the thermostat itself.
I decided to try a factory reset on the problematic thermostat. Here’s what I did:
- Factory Reset: I performed a factory reset on the thermostat by holding down the mode button for 10 seconds until the LED started flashing.
- Re-pairing: After the reset, I re-paired the thermostat with the C7 hub following the manufacturer’s instructions.
- Testing: I tested the thermostat to ensure it was responding to mode changes both through the hub and directly on the device.
Fortunately, the factory reset and re-pairing process worked, and the thermostat is now functioning as expected. I wanted to share this experience in case others are facing similar issues with their Z-Wave devices. It’s always a bit nerve-wracking when a device stops working, but with persistence and the support of the community, solutions can be found.
If anyone has additional insights or tips on troubleshooting Z-Wave devices, I’d love to hear them! Happy home automation everyone! 
暖气